99302domain: NAppears in sequencesQuadratic invariants.at n=5A000807Numbers n such that sigma(phi(n)) = sigma(n) - phi(n).at n=8A230371a(n) is the largest k such that the sum of k consecutive reciprocals 1/p_n + ... + 1/p_(n+k-1) does not exceed 1 (where p_n = n-th prime).at n=38A327600